Ir = current in receiver aerial in microamperes; about 5 microamperes for a just audible signal with detectors available in 1913. On the left side of the equation.
Is = current in sending aerial in amperes. For this demonstration, this is set to 2 amperes, a common value for pack sets in 1913.
h1 & h2 = sending and receiving aerial heights in feet. Continuously variable
for this demonstration by clicking and dragging the antennas up or down.
D= distance of transmission in kilometers. Either 30 or 500 Km in this demonstration.
w= wavelength in meters. Either 200 meters or 10 meters in this demonstration. Pack sets of 1913 would be more likely on 200 meters, transmitters of today on 10 meters.
e= 2.72, the natural (Napierian) base.